conclude vs nullify

conclude

verb
  • To shut off; to restrain; to limit; to estop; to bar; generally in the passive. 

  • To come to a conclusion, to a final decision. 

  • To end; to come to an end. 

  • to deduce, to infer (develop a causal relation) 

  • To bring to an end; to close; to finish. 

  • To bring about as a result; to effect; to make. 

nullify

verb
  • To make of no use or value; to cancel out. 

  • To prevent from happening. 

  • To make legally invalid. 

How often have the words conclude and nullify occurred in a corpus of books? (source: Google Ngram Viewer )